And the transaction time shows up as 21.06.2011 20:17.I later tried to withdraw a smaller amount, and that went through, but I'm still missing a chunk of bitcoins from the earlier transaction.How can I get in contact with someone who can help me?

Sometimes transactions can take up to a few hours to be included/confirmed in worst case, this is normal.

If you have any questions, you can ask for support by sending a message to the e-mail address shown on the bottom of any of the pool's webpage.